The fuel level of an automobile is typically measured using a variable resistor mechanism mounted in a fuel tank. The variable resistor mechanism may include a sender card having a variable resistor and a float having a float arm. The float arm can be pivotally mounted to the sender card and can include a wiper for making a connection thereon. The position of the float arm varies as the float rises and falls with the fuel level, and accordingly, the rising and falling of the float can also cause a movement of the wiper. Depending on the position of the wiper on the variable resistor, the resistance value will differ, which can be translated into a voltage level representing the fuel level in the fuel tank. The voltage level can be transmitted to a fuel gauge on the instrument panel of an automobile to indicate the level of fuel remaining in the fuel tank.
Since the sender card is located within the fuel tank and is frequently immersed in fuel, contamination can form on electrical components located thereon. This contamination can be non-conductive and can generate inaccurate voltage level readings from the sender card.
Techniques for dealing with contamination presently available, for example, place contamination resistant coatings on the electrical components. These contamination resistant coatings can contain conductive metals that may not be chemically reactive with fuel such as gold, palladium, copper-nickel alloys and noble metals. However, use of these contamination resistant coatings may, for example, increase the cost of manufacturing the sender card. Additionally, for example, if contamination forms on electrical components on the sender card even though the electrical components contain a contamination resistant coating, there may not be a mechanism by which contamination can be removed after it has been formed.